OP doesn't have DVD based NAV.I have a 2006 coupe with the DVD based navigation. I took out the disc and it was version 7.1, the newest version out for our DVD based navi's are 7.6.
Here is how to upgrade it to the newest version for the DVD based peeps...
(Have to know how to download torrents fyi)
The DVD cost $150 on the website... screw that, if you are somewhat computer literate you can upgrade it for free.
1. First goto a torrent website and search for "Nissan navigation", download the 7.6 version of the DVD.
2. You need a Dual layer DVD because the file is around 7 gigabytes (bigger than a regular DVD)
3. Burn the image to a dual layer DVD using ImgBurn
4. Pop DVD into your navigation system located above glove box